Prosthetic implants such as meshes, combination mesh products or other porous prostheses are commonly used to provide a physical barrier between types of tissue or extra strength to a physical defect in soft tissue. However, such devices are often associated with post-surgical complications including post-implant infection, pain, excessive scar tissue formation and shrinkage of the prosthesis or mesh. Excessive scar tissue formation, limited patient mobility, and chronic pain are often attributed to the size, shape, and mass of the implant and a variety of efforts have been undertaken to reduce the amount of scar tissue formation. For example, lighter meshes using smaller fibers, larger weaves, and/or larger pore sizes as well as meshes woven from both non-resorbable and resorbable materials are in use to address these concerns.
For treating acute pain and infection, patients with implanted prostheses are typically treated post-operatively with systemic antibiotics and pain medications. Patients will occasionally be given systemic antibiotics prophylactically; however, literature review of clinical trials does not indicate that systemic antibiotics are effective at preventing implant-related infections.
In 1992, it was reported that nosocomial infections involved over 2 million patients each year and cost the healthcare systems over 4.5 billion dollars annually.1 Today, these numbers are undoubtedly much higher. Surgical site infections, involving approximately 500,000 patients, represent the second most common cause of nosocomial infections and approximately 17% of all hospital-acquired infections.2 The incidence of infections associated with the placement of pacemakers has been reported as 0.13 to 19.9% at an average cost of $35,000 to treat these complications which most often involves complete removal of the implant.3,4 
Post-operative infection is tied to three elements: lack of host defense mechanisms, surgical site and bacteria present at the time of device implantation.5 The general health of the patient (i.e., the host factor) is always important; however, since many patients requiring surgery are compromised in some way—and there is little that can be done to mitigate that factor—controlling the other two factors becomes important.
Studies have shown that patients are exposed to bacterial contamination in the hospital, especially in the operating room (OR) and along the route to the OR6 In fact, bacterial counts of up to 7.0×104 CFU/m2 have been found in the OR dressing area.6 Recent improvements in air handling and surface cleansing have reduced the environmental levels of infectious agents, but not eliminated them. Consequently, further means to reduce bacterial contamination or to reduce the potential for bacterial infection are desirable.
Controlling the inoculation levels is the third component to the intra- and post-operative surgical infection control triad. One aspect to microbial control is the use antibiotics. For example, one practice advocates the administration of systemic antibiotics within 60 minutes prior to incision, with additional dosing if the surgery exceeds 3 hours.5 Such pre-incision administration has shown some positive effects on the incidence of infection associated with the placement of pacemakers.7 An adjunctive approach to managing the potential for implant contamination has been the introduction of antimicrobial agents on implantable medical devices.8,9 
This approach was initially developed to create a barrier to microbial entry into the body via surface-penetrating devices, such as indwelling catheters,9-11 The antimicrobial agents were applied in solution as a direct coating on the device to prevent or reduce bacterial colonization of the device and, therefore, reduce the potential for a device-related infection. While a number of clinical trials have demonstrated that antimicrobial coating on devices, such as central venous catheters reduce device colonization, reduction of infection has not been statistically significant although the numerical trends show a reduction in patient infection.12-18 These results are highly relevant since they tend to establish that, with proper aseptic and surgical techniques as well as administration of appropriate antibiotic therapy, the use of surface-modified devices has a positive impact on the overall procedural/patient outcome.12,13 
The development of post-operative infection is dependent on many factors, and it is not clear exactly how many colony forming units (CFUs) are required to produce clinical infection. It has been reported that an inoculation of 103 bacteria at the surgical site produces a wound infection rate of 20%.5 And while current air-handling technology and infection-control procedures have undoubtedly reduced the microbial levels in the hospital setting, microbial contamination of an implantable device is still possible. It is known that bacteria, such as Staphylococcus can produce bacteremia within a short time after implantation (i.e., within 90 days) with a device or lay dormant for months before producing an active infection so eradication of the bacterial inoculum at the time of implantation is key and may help to reduce late-stage as well as early-stage device-related infections.22 
For example, the combination of rifampin and minocycline has demonstrated antimicrobial effectiveness as a coating for catheters and other implanted devices, including use of those drugs in a non-resorbable coating such as silicone and polyurethane.13, 19-21 The combination of rifampin and minocycline has also been shown to reduce the incidence of clinical infection when used as a prophylactic coating on penile implants.
The parent case of this application (U.S. Ser. No. 11/672,929) describes a bioresorbable polymer coating on a surgical mesh as a carrier for the antimicrobial agents rifampin and minocycline. Such meshes can be fashioned into a pouch of various sizes and shapes to match the implanted pacemakers, pulse generators, defibrillators and other implantable medical devices. The addition of the antimicrobial agents permits the pouch to deliver antimicrobial agents at the implant site and thus to provide a barrier to microbial colonization of a CRM during surgical implantation as an adjunct to surgical and systemic infection control.
The present invention addresses these needs (preventing or inhibiting infections) as well as others, such as pain relief and inhibition or reduction of scar tissue, fibrosis and the like, by providing temporarily stiffened meshes formed into pouches or other receptacles to hold an implantable medical device upon implantation.